Tru Oil or Formby's tung oil

Vic D

Vic D

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I need to finish my CBU and it's either Formby's tung oil which I can get locally or Tru Oil if I wanna drive a while. The CBU is spruce, spanish cedar and poplar.

Which do you guys think is best and why? I have a can of spray shellac too.

Also... do any of you CBU makers a the wah effect when you rock the CBU against your belly? I mean it's cool and stuff, pretty prounounced too.
 
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Vic D said:
...it's either Formby's tung oil ... or Tru Oil ... I have a can of spray shellac too...
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Well, I have seen instruments with a Tru Oil (or other gun oil) finish and I was really impressed, both by the sheen and smoothness and by the hardness. I don't recall whether the smell of the oil made any impression on me - so I guess it didn't. Anyway, I guess it's up to you.

Spray shellac sounds interesting, although I wonder what the finish is like compared to french polishing. We still rub it on with polishing pads, the old-fashioned way. Have you used spray-on shellac before?
 
Most builders cringe at the sound of someone using an oil finish. The theory is that the oil clogs the pores and muffles the sound, although I don't know if it's been scientifically proven.

Having said that, I like Tru-Oil. It's a blend and dries more like varnish and gives you a nice satin finish. Formby's isn't a pure tung oil either, so the results may be the same.
 
DaveVisi said:
Most builders cringe at the sound of someone using an oil finish. The theory is that the oil clogs the pores and muffles the sound, although I don't know if it's been scientifically proven.

Having said that, I like Tru-Oil. It's a blend and dries more like varnish and gives you a nice satin finish. Formby's isn't a pure tung oil either, so the results may be the same.
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That's a great point Dave. I do allot of wood turning and one popular wood is Norfolk pine a softwood of very light weight similar to spruce and cedar in density. The popular way of finishing bowls made from Norfolk Pine is using boiled linseed oil which is very similar to Tru-Oil (which I use on my gunstocks). The boiled linseed oil will sink into the Norfolk Pine and sink completely into the grain and when dried changes the density of the wood into a heavier more solid piece like a hardwood. It gives this wood a translucency similar to tortoise shell when dried thus being a popular finish. On a piece of cedar I'm guessing an oil finish like Tru-oil or Tung-oil would do the same thing and have an effect on the tonal quality of the wood. These oil finishes would also darken the wood quite a bit changing the looks of the cedar if that matters. I would recommend a surface coat on softwoods like cedar, spruce, redwood to preserve the tonal quality. The aerosol might be a better choice. My 2 cents.
 
The theory is that the oil clogs the pores and muffles the sound, although I don't know if it's been scientifically proven.
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I don't get it. If clogging pores is a problem, why do we use grain filler on mahogany, koa and other open-grained woods? Isn't the point to fill (clog) those pores for a more level finish?
 
Exactly, fillers are used when you want a mirror smooth finish. Oil finishes can go beyond the filling of surface pores of wood, it can saturate the cells and solidify them if used too liberally which is good for most woods you want to preserve but not in a musical instrument that you want to preserve the natural tonal qualities. My R&L Koa 'ukulele has a satin finish with no fillers so I can see the pours and grains of the wood and feel them, and I like it the natural look, and she sings beautifully with this almost naked finish.
 
Search UU for this. "William King's oil finish/lacquer regime" Originally posted by Pete Howlett. I can't figure out how to link it. Sorry.
Doug
 
The sad thing about "Formby's Tung Oil Finish" is there is no tung oil in the bottle

I guess since they call it a "Tung Oil Finish" and not "Tung Oil" they can get away with it.

Did you ever notice that there is more lemons in Pledge than there is in lemon flavored drinks?

There are many successful luthiers that are on both sides of the fence when it comes to oil vs lacquer.
 
When I used Tru-oil I sanded the instrument to about 600 grit then wiped on several coats of amber shellac, rubbed it out smooth with 0000 steel wool then followed with six or so coats of tru-oil. I could only put on about two coats a day and it takes forever for it to completely cure but it was well worth the effort.
 
DaveVisi said:
Most builders cringe at the sound of someone using an oil finish. The theory is that the oil clogs the pores and muffles the sound, although I don't know if it's been scientifically proven.
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I would point out that Stradivarius (along with other builders of stringed instruments at the time) used oil-based finishes - so I think this statement has to be taken not just with a grain, but with a good dose of salt.
 
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Oil based and actual oil are not necessarily the same thing. Oil based finishes were pretty much all that was available from time immemorial until the advent of acrylic, and epoxy finishes which replaced oil based finishes in many areas they being relatively modern. Stradivari used a oil based varnish of his own secret formulation which was more a surface coat. Tru-oil and tung-oil are penetrating oil meant to be rubbed into the surface which probably isn't ideal for the OP's softwood Cedar cigar box.
 
Doug said:
Search UU for this. "William King's oil finish/lacquer regime" Originally posted by Pete Howlett.
Doug
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I followed this regime on my current ukes because I didn't think I could succesffully use lacquer with winter temperatures and the limitations of my current working space. Oil definitely darkened the usually light and lively mango wood. I much prefer the lighter color obtained with a lacquer finish. I'm currently "repairing" my newest uke, which did NOT have the tone I was expecting. I'm sanding down the top and back and redesigning the bridge to make it lighter. Then I"ll take Brad's advice and string up the instrument and listen to the tone. If satisfactory, I'll be putting oil finish back on the top and sides, so it will be an experiment in how oil affects tone.
 
curlykoa said:
Oil definitely darkened the usually light and lively mango wood.
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No doubt about it oil will darken wood.

But different oils darken differently.

Most finishes contain boiled linseed oil, this oil darkens wood the most.

Next comes tung oil (waterlox is my favorite). This darkens wood noticeably less.

Lastly, walnut oil (not the type you get in a supermarket) hardly darkens woods.
 
Another vote for Waterlox which is technically a "long oil varnish" based on tung oil with alkyd and phenolic resins added. It's great as a finish or as a "tie coat" presealer under other surface finishes. It helps adhesion tremendously under polyurethane sealers and polyester build and top coats. I also use it to lock in dye stains when I do sunbursts directly on bare wood with metal acid dyes.
 
I did this mahogany hardtail strat in Tru Oil. I wasn't particularly impressed with it. It scuffed REALLY easy. It didn't darken the wood all that much.
4249688682_021ba254df_o.jpg
 
About Birchwood-Casey Tru-Oil. It's a linseed oil based varnish, not an oil finish but a varnish finish. It's good stuff, I've been using it since 1964 on gunstocks, bamboo fly rods, some furniture touch-up.

About Formbys Tung-Oil Varnish. I don't care what's in it, it's good. I used to to refinish an oak secretary, three kit fiddles and a couple of years ago I used it as the finish on a Musicmaker lever Harp kit that I made for my wife. The end result on that job gave me a finish that looks like the finish on my KoAloha ukes. It's easier to use than Tru-Oil in my opinion.

But the big secret to any finish is wood preparation. If it's not properly sanded it shows, but that's how we learn. Enjoy the ride.

Jude
 
Uncle Taco, very nice. One of my future projects but mine will be a "Blackie" ( copy of David Gilmour's ). Thanks for the info.

Thanks everyone, I can see this is going to take some more thought. I don't want to affect the tone in a bad way and I want a good hard surface that will last. Think I'm about to just do the Formby and cross my fingers.
 
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Ahnko Honu said:
Stradivari used a oil based varnish of his own secret formulation which was more a surface coat.
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Stradivari used the same methods as the other masters of the day. If he had a 'secret formula' then only the proportions of one component to the others, which may or may not have been different from the other masters' formulas.

You're right that it was a "surface coat" inasmuch as he (and the others) used a siccative oil sealer which was then covered by oil varnish. You can buy this stuff - both the oil sealer and the oil varnish from places like Kremer. And BTW, shellac varnishes (i.e. alcohol-based) were in use at the time so Stradivari did have a choice. And both shellac and oil varnish are still very much in use nowadays, at least by master luthiers with small operations.
 
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